ELECTRICAL ENGINEERING

PRACTICE SET- 2

Q.1:- Two materials have resistance temperature coefficients of 0.004 and 0.0002 respectively at a given temperature. In what ratio should the wires made of these materials be connected in series so as to have an overall temperature coefficient of 0.002?

(a) 1:2(b) 2:3(c) 9:10(d) 15:16

Q.2:- Consider the two fields,

E = 120 � cos (10⁶� t- x) V / m

And

H = A cos (10⁶� t- x) / m.

The values of A and β which will satisfy the Maxwell’s equation in a linear isotropic, homogeneous, loss-less-medium with = 8 and

= 2 will be

A (in A / m)β (in rad / m)

(a)

10.0105

(b)

10.042

(c)

20.0105

(d)

20.042

Q.3:- A chopper operating at a fixed frequency is feeding an R-L load. As they duty ratio of the choppe is increased from 25% to 75%, the ripple in the load current.

(a)

Remains constant.

(b)

Decreases, reaches a minimum at 50% duty ratio and then increases.

(c)

Increases, reaches a maximum at 50% duty ratio and then decreases.

(d)

Keeps on increasing as the duty ratio is increased.

Q.4:- A sinusoidal waveform, when observed on an oscilloscope, has a peak to peak amplitude of 6cm. If the vertical sensitivity setting is 5 V / cm, the rms value of the voltage will be

(a) 10.6 V(b) 11.1 V(c) 12.6 V(d) 15 V

Q.5:- Which of the following is an example of an open-loop system?

(a)

Household refrigerator.

(b)

Respiratory system of an animal.

(c)

Stabilization of air pressure entering into a mask.

(d)

Execution of a program by a computer.

Q.6:- A binary tree T has n leaf nodes. The number of nodes of degree 2 in T is

(a)

(a) n(b) n – 1

(b)

(c) n(d)